Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea.
Angew Chem Int Ed Engl. 2020 Sep 28;59(40):17511-17516. doi: 10.1002/anie.202008435. Epub 2020 Aug 11.
A photocatalytic double umpolung strategy for the vicinal aminopyridylation of ketones was developed using pyridinium N-N ylides. The inversion of the polarity of the pyridinium N-N ylides by single-electron oxidation successfully enables radical-mediated 1,3-dipolar cycloadditions with enolsilanes formed in situ from ketones, followed by homolytic cleavage of the N-N bond. Intriguingly, the nucleophilic amino and electrophilic pyridyl groups in the ylides can be installed at the nucleophilic α-position and electrophilic carbonyl carbon, respectively, which are typically inaccessible by their innate polarity-driven reactivity. This method accommodates a broad scope, and the utility was further demonstrated by the late-stage functionalization of complex biorelevant molecules. Moreover, the strategy can be successfully applied to enamides.
发展了一种光催化双重反转策略，用于通过吡啶鎓 N-N 叶立德实现酮的邻位氨基吡啶化。通过单电子氧化将吡啶鎓 N-N 叶立德的极性反转，成功地实现了与酮原位形成的烯基硅烷的自由基介导的 1,3-偶极环加成反应，然后 N-N 键发生均裂。有趣的是，叶立德中的亲核氨基和亲电吡啶基可以分别在其固有极性驱动的反应性通常无法到达的位置即亲核的 α-位和亲电的羰基碳上进行安装。该方法具有广泛的适用性，通过对复杂生物相关分子的后期官能化进一步证明了其实用性。此外，该策略可以成功应用于烯酰胺。
